Max Planck Institute for Developmental Biology, Spemannstrasse 35, 72076 Tübingen, Germany.
Development. 2012 Nov;139(21):4072-82. doi: 10.1242/dev.080879. Epub 2012 Sep 19.
The transition from vegetative to reproductive development is a central event in the plant life cycle. To time the induction of flowering correctly, plants integrate environmental and endogenous signals such as photoperiod, temperature and hormonal status. The hormone gibberellic acid (GA) has long been known to regulate flowering. However, the spatial contribution of GA signaling in flowering time control is poorly understood. Here we have analyzed the effect of tissue-specific misexpression of wild-type and GA-insensitive (dellaΔ17) DELLA proteins on the floral transition in Arabidopsis thaliana. We demonstrate that under long days, GA affects the floral transition by promoting the expression of flowering time integrator genes such as FLOWERING LOCUS T (FT) and TWIN SISTER OF FT (TSF) in leaves independently of CONSTANS (CO) and GIGANTEA (GI). In addition, GA signaling promotes flowering independently of photoperiod through the regulation of SQUAMOSA PROMOTER BINDING PROTEIN-LIKE (SPL) genes in both the leaves and at the shoot meristem. Our data suggest that GA regulates flowering by controlling the spatial expression of floral regulatory genes throughout the plant in a day-length-specific manner.
从营养生长到生殖生长的转变是植物生命周期中的一个中心事件。为了正确地把握开花的诱导时间，植物会整合环境和内源性信号，如光周期、温度和激素状态。植物激素赤霉素（GA）长期以来被认为可以调节开花。然而，GA 信号在开花时间控制中的空间贡献还知之甚少。在这里，我们分析了野生型和 GA 不敏感（dellaΔ17）DELLA 蛋白在拟南芥中的组织特异性过表达对花转变的影响。我们证明，在长日照下，GA 通过促进开花时间整合基因如 FLOWERING LOCUS T（FT）和 TWIN SISTER OF FT（TSF）在叶片中的表达，而不依赖于 CONSTANS（CO）和 GIGANTEA（GI）来影响花转变。此外，GA 信号通过调节叶片和茎分生组织中的 SQUAMOSA PROMOTER BINDING PROTEIN-LIKE（SPL）基因，在不依赖光周期的情况下促进开花。我们的数据表明，GA 通过以特定于日长的方式控制植物中整个植株中花调控基因的空间表达来调节开花。
